Loans Modified as TDRs have Subsequently been Fully or Partially Charged-Off (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012 SecurityLoan	Sep. 30, 2011 SecurityLoan	Sep. 30, 2012 SecurityLoan	Sep. 30, 2011 SecurityLoan
Financing Receivable, Modifications [Line Items]
Number of Loans	3,305	2,536	9,938	7,324
Amount Defaulted	$ 99	$ 107	$ 519	$ 274
Commercial Loan
Financing Receivable, Modifications [Line Items]
Number of Loans	195	245	652	513
Amount Defaulted	2	13	33	23
Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Number of Loans	13	29	96	37
Amount Defaulted	12	32	176	37
Residential Mortgage
Financing Receivable, Modifications [Line Items]
Number of Loans	116	96	427	536
Amount Defaulted	30	20	64	112
Credit Card
Financing Receivable, Modifications [Line Items]
Number of Loans	2,536	1,803	7,452	5,366
Amount Defaulted	14	9	42	27
Other Retail
Financing Receivable, Modifications [Line Items]
Number of Loans	189	141	531	397
Amount Defaulted	4	2	8	9
Total loans, excluding GNMA and covered loans
Financing Receivable, Modifications [Line Items]
Number of Loans	3,049	2,314	9,158	6,849
Amount Defaulted	62	76	323	208
Loans purchased from GNMA
Financing Receivable, Modifications [Line Items]
Number of Loans	248	222	731	475
Amount Defaulted	34	31	106	66
Covered loans
Financing Receivable, Modifications [Line Items]
Number of Loans	8		49
Amount Defaulted	$ 3		$ 90